After I discovered Thorn had two grown sons, I thought it was only right to keep them in Thorn’s life somehow. What would a next-generation version of Thorn look like? What Thorn’s kid’s passions be? Because Thorn is so devoted to the natural world, it seemed obvious that at least one of his sons should share that commitment. I decided to ratchet up that interest in environmental issues. A son who out-Thorned Thorn. I’d been fascinated for some time with the views of eco-radicals. In particular, I began to focus on ELF, the Earth Liberation Front, a loosely organized group of environmental activists around the U.S.

The question I asked myself was this: If Flynn got involved with an ELF cell in South Florida, what might their target be? The biggest target I could imagine is Turkey Point, the nuke plant on the edge of Biscayne Bay in southern Miami-Dade County. I’d boated past the plant many times and always been struck by its awesome and somewhat ominous presence.

Then I remembered an old friend of mine, wildlife biologist Joe Wasilewski. I knew that one of Joe’s many projects was working with crocodile nesting areas in the cooling canals of Turkey Point. Joe was generous enough to take me out on an airboat and cruise through those cooling canals, a journey which gave me a close-up view of the plant itself and made me start to wonder how a group of naïve environmental activists could defeat the major league security of a nuclear power plant in order to stage some kind of publicity stunt.

That was the nugget of the story. As is always the case with a Thorn novel, once I know the subject matter the next big hurdle I must cross at the outset is to answer this question: “How the hell can I get the reluctant, anti-social, loner Thorn to engage in the next crisis?” Well, in this case, having a son who’s mixed up with a band of not-so-non-violent activists made answering that question a lot easier than usual.